The Potential Fungal Pathogens of Euonymus japonicus in Beijing, China

Diversity of Colletotrichum species associated with anthracnose on Euonymus japonicus and their sensitivity to fungicides

As an evergreen shrub, Euonymus japonicus plays a crucial role in urban landscape construction, and its growth is affected by severe foliar anthracnose caused by Colletotrichum spp. However, the biodiversity of Colletotrichum species associated with anthracnose on E. japonicus remains undetermined. This study involved a two-year collection of E. japonicus leaf samples with typical anthracnose symptoms from 9 districts in Beijing, China. A total of 194 Colletotrichum isolates were obtained, and eight Colletotrichum species were subsequently identified using morphological characteristics and molecular identification with the ACT, GADPH, CHS, TUB2, and CAL genes, as well as the rDNA-ITS region. These species included Colletotrichum aenigma, C. fructicola, C. gloeosporioides, C. grossum, C. hebeiense, C. karstii, C. siamense, and C. theobromicola with C. siamense being the most prevalent (57%), followed by C. aenigma and C. theobromicola. Furthermore, C. fructicola, C. grossum and C. hebeiense are reported for the first time as causal agents of anthracnose on E. japonicus worldwide, and C. karstii is newly reported to be associated with E. japonicus anthracnose in China. Pathogenicity tests revealed that all tested isolates exhibited pathogenicity in the presence of wounds, emphasizing the need to avoid artificial or mechanical wounds to prevent infection in E. japonicus management. The EC50 values of five fungicides, namely difenoconazole, flusilazole, tebuconazole, hexaconazole, and prochloraz, were found to be less than 10 mg/L, indicating their strong potential for application. Notably, the EC50 of prochloraz was less than 0.05 mg/L for C. theobromicola. These findings offer valuable insights for the management of anthracnose on E. japonicus.

Morphology and Phylogeny Reveal Three New Species of Cytospora Associated with Tree Cankers in China

Cytospora (Cytosporaceae, Diaporthales) is a fungal genus that usually inhabits plants as endophytes, saprobes, as well as pathogens. Species of this genus are characterized by possessing allantoid hyaline conidia and ascospores. Samples with typical Cytospora canker symptoms on Prunus davidiana, P. padus and Salix sp. were collected in Tibet and Xinjiang, China. Species were identified using both morphological and molecular approaches of combined loci of internal transcribed spacer region rDNA (ITS), the partial actin (act) region, RNA polymerase II second largest subunit (rpb2), the translation elongation factor 1-alpha (tef1) gene and the partial be-ta-tubulin (tub2) gene. Six isolates in the present study formed three distinct clades from previously known species. Cytospora hejingensis sp. nov. from Salix sp., C. jilongensis sp. nov. from P. davidiana and C. kunsensis from P. padus were proposed herein. The current study improves the understanding of species concept in Cytospora.

Multigene phylogeny and morphology reveal three new species of Cytospora isolated from diseased plant branches in Fengtai District, Beijing, China

Members of Cytospora include saprobes, endophytes and important plant pathogens, which are widely distributed on various wood hosts and have a wide global distribution. In this study, the species definitions were conducted, based on multigene phylogeny (ITS, act, rpb2, tef1-α and tub2 genes) and comparisons of morphological characters. A total of 22 representative isolates obtained from 21 specimens in Fengtai District of Beijing City were identified as seven species of Cytospora, including four known species (C.albodisca, C.ailanthicola, C.euonymina, C.haidianensis) and three novel species (C.fengtaiensis, C.pinea, C.sorbariae). The results provide an understanding of the taxonomy of Cytospora species associated with canker and dieback diseases in Fengtai District, Beijing, China.

Morphology and molecular analyses reveal three new species of Botryosphaeriales isolated from diseased plant branches in China

The Botryosphaeriales represents an ecologically diverse group of fungi, comprising endophytes, saprobes, and plant pathogens. In this study, taxonomic analyses were conducted based on morphological characteristics and phylogenetic analyses of multi-gene sequence data from four loci (ITS, LSU, tef1-α, and tub2). Thirteen isolates obtained from Beijing and Yunnan Province were identified as seven species of Botryosphaeriales, including Aplosporellajaveedii, Dothiorellaalpina, Phaeobotryonaplosporum and Ph.rhois, and three previously undescribed species, namely Aplosporellayanqingensis, Dothiorellabaihuashanensis, and Phaeobotryonplatycladi. Additionally, the new records of Dothiorellaalpina from the host species Populusszechuanica, Phaeobotryonaplosporum from Juglansmandshurica, and Phaeobotryonrhois from Populusalbavar.pyramidalis are included.